There have recently been in practical use contactless IC cards that can make information exchange with a data processor such as a reader/writer by radio communications. Such contactless IC cards are applied as a prepaid card, commutation ticket and the like in a wide range. Since the contactless IC card has not to be put in physical contact with any data processor when updating information in the card, it can advantageously be used without being taken out of its carrying case such as a wallet or the like each time.
To display information such as a balance or the like in an ordinary prepaid card, the card is passed through a puncher or printer provided in a reader/writer to punch a hole in the card itself or make a rewrite printing on the card itself. However, since the contactless IC card has not to be passed through such a reader/writer, such information cannot be displayed in such a manner.
On this account, it has been proposed to provide, in the contactless IC card, a display device such as a liquid crystal or organic EL (electroluminescence) which is to be powered by a built-in battery to display such information. In the case of this contactless IC card, however, since the display device has to always be powered from the battery to keep the information displaying, the power in the battery will gradually be decreased. To keep the information display for a long time, the battery should be replaced or recharged.
Also, a contactless IC card powered by a solar call is known from the disclosure in the Japanese Patent Application Laid Open No. 108904 of 1993, for example. However, this contactless IC card cannot display any information in a place where it is not exposed to any sufficient light.
Further, a contactless IC card using a ferroelectric liquid crystal display panel is known from the disclosure in the Japanese Patent Application Laid Open No. 154215 of 1998. Generally, the ferroelectric liquid crystal has at least two stable states in the direction of alignment, and is stabilized in one of the two states depending upon the direction of impressed electric field to have the molecules thereof kept in the direction of alignment even when the electric field is removed. Therefore, use of the ferroelectric liquid crystal display panel permits to hold the display even after no power is available.
The storage display device as disclosed in the above-mentioned Japanese Patent Application Laid Open No. 154215 of 1998, if used in a contactless IC card, takes a long time for information write and needs a high voltage and thus a relatively large power to work, the contactless IC card has to be held over a reader/writer for a longer time.